PARTICULATE ORGANIC MATTER AS A SOIL QUALITY INDICATOR OF SUGARCANE PLANTATIONS IN EAST JAVA

摘要

This study is aimed to test the hypothesis that the soil quality of sugarcane plantations closely linked to the particulate organic matter (POM) and earthworm populations. The research was conducted at five sites in Malang, East Java. The sites were selected based on differences in average annual rainfall and two types of soil management : with and without organic input. Soil samples taken from a depth of 0-20 cm were analyzed total organic C (TOC), total N, POM-C, and POM-N and earthworm population density and biomass. The TOC were corrected by the clay content using pedotransfer equations so obtained TOCref. The interaction between differences in annual rainfall and two types of the treatments significantly (p<0.05) influenced TOC, total N, POM-C, POM-N, earthworm density and biomass. The soils treated with organic input had higher TOC (18%), total N (28%), POM-C (70%), POM-N (64%), earthworm density (89%) and biomass (92%) than the soils without organic input. Increase in TOC, TOC/TOCref, and POM-C tend to be followed by an increase in earthworm density (r=0.590;0.667;0.738) and biomass (r=0.622;0.732;0.581). Thus, it can be suggested that the POM-C is the most sensitive measurement for determining soil quality in sugarcane plantations, the earthworm population density may be used as an indicator of decreased soil quality of sugarcane plantation.